Office chair



FIG. 1 is a perspective view of the ornamental design for an office chair according to the invention.

FIG. 2 is a rear perspective view thereof.

FIG. 3 is a left side elevational view, of which the right side view is a mirror image thereof.

FIG. 4 is a front elevational view thereof.

FIG. 5 is a rear elevational view thereof.

FIG. 6 is a top plan view thereof; and,

FIG. 7 is a bottom plan view thereof. 

The ornamental design for an office chair, as shown and described. 